Mobile IP is a technology for a mobile node which uses IP. When the roaming mobile node is connecting to a remote network, if the mobile node has registered an address, obtained from a current network, to a home agent (HA), a home network transmits data to the mobile node located in the remote network.
A mobile IP standard is comprised of two parts: a mobile IP agent and a mobile node. A mobile IP agent takes charge of a virtual routing service for routing a packet to the registered mobile node.
The mobile IP is a sort of protocol which registers its own location to a home agent in a home network in order to provide IP mobility when the mobile node moves to a home network or a visiting network as shown FIG. 1. At present, a mobile IP-based handover solution is mainly used in order to support a vertical handover between networks.